Throat plate for overedge sewing machine



Mai-ch 5', 1963 J. M. wAsHBURN THRoA'r PLATE FOR ovEREDGE sEwING MACHINE 5 Sheets-Sheet 1 Filed Aug. 19, 1960 [Iz ven o r: Jbkrv M Wzskhurn y @uw M 70's Aorneys March 5, 1963 J. M WASHBURNrr THROAT PLATE FOR OVEREDGE SEWING MACHINE Filed Aug. 19, 1960 Invnzor John MWshbumz March 5, 1963 J. M. WASHBURN 3,079,882

THRoAT PLATE FOR OVEREDGE SEWING MACHINE:

Filed Aug..19, 1960 3 Sheets-Sheet 3 figg. 6. 2&9. z Eg. a.

Invenor: Toh n MT/laskh urn @mm/MM iinited dentes s tiene 3,97%,382 THRGAT PLATE Fll @VEREDGE SEWENG MASHNE .lohn M. Washburn, West Hartford, Conn., assigner to Tae Marrow Machine Company, Hartford, Conn., a corporation of Connecticut Filed Aug. 19, i969, Ser. No. 56,643

Z Claims. (El. lf2-2&9)

This invention relates to overedge sewing machines, and more particularly to throat plates for use in overedge sewing machines wherein multiple needles are employed tov form fabric penetrating loops passing through the fabric at different distances from the fabric edge.

The invention has particular utility in the formation of overedge seams where two plies of fabric are joined by the seam in edge to edge abutment. In the formation of overedge seams, two plies of fabric to be joined are fed through the sewing machine with one ply of fabric overlying the other and with the edges of the plies along which the seam is to extend invertical alignment with each other. The machine passes a loop of thread downwardly through both plies of fabric. Elements of the machine manipulate the loop to draw the loop outwardly beneath the lowermost ply to the fabric edge. This loop may be then drawn upwardly around the edges of both plies and brought to a point overlying the uppermost ply of fabric at which the loop is then pierced by a subsequent fabric penetrating loop or, in other types of seams, a covering thread loop may be passed through the fabric penetrating loop, brought upwardly around the edge and over the upper surface of upper ply to be pierced by a subsequent fabric penetrating loop. ln either case, the seam, as completed by the machine, inds the two plies of fabric in overlying relationship with he seam extending along a common edge of the two plies. ln many cases, after the fabric has been seamed, it is desirable to open out the two plies about the seam so that when the two plies are placed on a llat surface, the see-.med edges of the two plies are in edge to edge abutment, rather than the overlapping relationship in which the seam was formed by the machine.

It is frequently desirable to form an overedge seam by forming two series of fabric penetrating loops by ernploying a pair of needles in side by side relationship, the fabric penetrating loops formed by one needle penetrating the fabric at points lying along a iirst line extending parallel to the edge of the fabric and the loops formed by the second needle penetrating the fabric at points lying along a second line spaced at a greater distance from the fabric edge than the line of penetration points of the first needle. The fabric enclosing capacity of the loops formed by the respective needles is determined during the stitch forming operation and hence, when the fabric plies are subsequently opened out to form an abutted edge seam, those loops which penetrate the fabric at points most distant from the fabric edge must be longer than the loops penetrating the fabric at points more closely adjacent the fabric edge. In the complete abutted seam, ir' the loops which penetrate the fabric at points most distant from the fabric edge are not sufficiently and uniform-.ly longer than the loops which penetrate the fabric nearest the fabric edge, a greater tension will be placed on the loops of one needle thread than on the loops of the other needle thread.

It is a primary object or" the invention to provide an overedge sewing machine employing two or more needles to form two or more series of fabric penetrating loops wherein the fabric enclosing capacity of the various loops may be determined during the stitch forming operation to achieve substantially equal tension in all needle threads e it,

Patented Mar.

when the work material is subsequently opened out to form an edge abutted seam.

Other objects and features of the invention will become apparent by reference to the following specification and to the drawings.

4In the drawings:

FIG. l is a perspective View of one type of seam which may be formed with the use of a throat plate embodying the present invention showing the seam as it is formed by the machine;

FlG, 2 shows the seam of FIG. 1 opened out into its completed form;

FIG. 3 is a front view, partially in section, with certain parts broken away or omitted, of a Morrow overedge machine;

lG. 4 is a plan View of a throat plate embodying the invention;

FIG. 5 is a side elevational view of the throat plate of FlG. 4;

FIG. 6 is a cross-sectional view taken on line -d of PEG. 4;

FIG. 7 is a partial cross-sectional view taken on line 7--7 of FIG. 4; and

FG. 8 is a cross-sectional view taken on line S-- of PIG. 4 showing the thread-fabric relationship during the seam formation.

It is believed the invention will be best understood by a brief description of the manner in which an overedge seam of the type with which the invention is concerned is formed. FG. 3 is a cross-sectional View, with certain parts omitted, of a well known Morrow overedge sewing machine. The machine includes upper and lower shafts 1li and l2 journalled in the machine frame ld for rotation and synchronously rotated by conventional means, not shown. A pair of thread carrying needles l5 and i3 are mounted in side-by-side relationship upon a needle carrier 2li which is driven in rotary oscillation about the axis of a pivotal support designated generally Z2. Needle carrier 2% is oscillated in a conventional manner by an eccentric pin 24; at the outer end of upper shaft l ln FIG. 3, the needles are shown at approximately the mid point of their rotary oscillation, the lower limit of movement of needles i6 and i3 locating the needles below the path of movement of lower looper 2e while the upper limit of movement locating the tips of needles f6 and 1S somewhat above looper 2S. For further details of the needle carrier and its movement relative to various parts of the machine, see United States Patent No. 2,755,757, granted on Iuly 24, 6 to Bernard N. Pierce.

Each of shafts lll and 12 carries a cylindrical cam such as 3l) and 32. Cam groove 34 in upper cam 3l? and carn groove 36 in lower cam 32 control the movement of upper loop-er 28 in a manner well known in the art while a second cam groove E8 in lower cam 32 controls the movement of lower looper 26. Movement of needle carrier 2l?, lower looper 2e and upper louper 2S is thus coordinated in a manner well known in the art to produce a seam such as that shown in FIG. 2 in the following manner.

Work material vto be seamed is placed upon ythe upper surface of a throat plate 4i! with the plies (Mi and M2) to be joined in overlapping relationship as in FlG. 1, the edge along which the seam is to be formed extending along edge 42 of throat plate 4G. Feeding mechanism (not shown) in the machine feeds the material in movement synchronized with needles 16 and 18 in a direction directly away from the observer in FIG. 3. Needles lo and i?, each carry a separate needle thread, thread 44 of FlG. 1 being carried on needle 16 while thread 4d is carried on needle 13. A third, or covering thread #l of FIG. V1

3 is carried by and passes through the eye 50 of lower looper 26.

Do'wnwa'rdl movement of' needles 16 and 18- from the' position of FIG. 3 carries the needles and their 'respective threads through both plies of work materials supported upon throat plate V40 at penetration points 52 and 54. Needles 16 and 1S pass downwardly through alignedopenings in throat plate 40 to a point where the thread loops-carried by the-respective needles'a're' located in the path ofm'o'vement Voflo'wer'l'ooper 26. VAt this time, ther lowerv looper move'stothe right from its' position in FIG. 3 and the point of the lower looper passes' between-the respective threads-44 and 46 and their needles 16 and 18. A loop of each of threads 44 and 46 is thus" retained on the lower looper .to the left andv below' eye' 50. This movement of -the lower looper also projects a loop of thread 48 through :the respective retained loops in threadsv 44 and 46.

The loop of thread 48 is carried to the rightby eyel 59 of lower looper 26 outwardly beyond edge` 42 of throat plate 40 at the time upper looper 2S moves'to a position below and to the left ofv eye 50 of lower looper 26, and the point 29 of the upper looper 28 passes upwardly between .the back side of lower looper `26 and the threadni, thus placing a loop of thread 4S inthe throat 29 of upper looper 2S. Theupper looper 28: car

ries this loop of thread 48 upward and-.over the plies of material supported by the throat plate 40 to a point where the next downward movement of needles 16 and 18, carrying ythreads 44 and 46 respectively, pass' through the loop of covering thread 48a Tension on thread 48 re# tains the respective loops of threads 44 and 46' in the manner best shown in FIG. 1 .as the lower looper returns to position shown in FIG. 3. The feeding mechanism of the machine (not shown) feeds the material one step away from the observer in FIG'. 3 so that the loop of covering thread 4S is passed through by the loops of needl'e'threads 44 and 46 in the'next subsequent stitch.

To permit the seam as shown in- FIG. l to be opened out into the relationship of FIG. 2,- 'the seam as completed byv the machine finds a certain amount of slackin the loops of threads 44 and 46. This amountof slack'i's determined by: the thickness of throat plate 40 since, as

formed by the machine, each Vof the loops' infthreads 44 and 46 pass beneath and around; stitch ingers'56 and 58 on .the throat plate. As indicated in FIG. l", those portions of the loops of thread 44 which' project to theri'ght of .the fabric edge in FIG; l-ie. the slackreferred to aboveare substantially equal inlengthY and fabric enclosing capacity to the corresponding portions of' the' loops of thread 46. However, as israpparent from FIG. 2, opening out of the fabric plies into the FIG. 2 relationship' takes up a much greater amount ofV slack-from the loops of thread 44uthanfrom the loops of' thread 46.' Tnus, the tension applied to thread' 44 in the completed; seam of FIG. 2 differs from the-tension appliedrto'tliread 46. To obtain equalA tension in' both threads, thelconventional throat plate shown in section in FIG'. ,3 isfreplaced with a throat plate 6D embodying the inventionand shown in FIGS. 4 through 8 of the drawings.Y

InFIGS. 4' through 8*,` a throat plate 60, designed to replace throat plate 40 of FIG. 3 is disclosed as'being`V formed with an elongate -opening62 within which feed dogs may be located to' feed workv material across Vthe throat*V tweenthe throat plate and vother cornponent'parts of A the machine. 'Ih'e'path of movement' of Aneedles16' and 18 isV indicated in cross-hatched are-as 16'V and 18' respec-A tively in FIG. 4.' As best seen'in PIG.V 4, the needles pass downwardly ladjacent a side edge 66 of throat plate 69 Iand rearwardly (with respect to the direction of feed of material indicated by arrow F) of a projection 68 which projects laterally outwardly from side edge 66.

Two sti-tch fingers 76 and 72 extend from projection 68 in parallel spaced relationship to side edge l66. As seen in FIG. 4, needle 16 passes ythrough the, throat plate between stitch finger. 70 and side edge 66 at a locationv adjacent the'base' of stitch finger'70, while needle.A 18 passes between stitchfingers `70` and 172,*adjacent their bases. As best seeninFIGS; 5 thrcruglrV 7, the upper side surfaces `of stitch lingers 70 and 72 lie in a generally horizontal plane coplanar with` the.. general top surface of throat plate 6i). The lower side surfaces'v 74 and` 76:-

of the respectivev stitch fingers 70' and 721 are inclined. upwardly in ar direction away from their respective bases.

so that loops of 4threads 44` and 46 formed around the-i respective stitch ingersare easily pulled' from the VVstitch iingersV as the' work material is'fed' through. the machine; As shown most clearly inFIGS..5 and 8, stitchfinger70 is Vsubstantially-thicker'in its vertical eX-tentthan is stitcl finger 72 and, as isaappa-rent from-FIG. 8, the variation in: thicknessA thus enables a substantially greater amountl of slack to be placed'v in the loops of thread 44Y (carried` by needle 16) than is placed in the -loopsof thread' 46 (carriedv by'needle 18) during-the formation of theiloopsY l an overedge sewing'V machine having av pailioff needles in side-by-side relationship; a throat plate'hav'ingY a side edge anda projection extending'laterally fromsaid' side edge, a rst elongate stitchA linger secured"v at its base to'said projection and extendinghorizontally from saldi projection in spaced parallel relationship'withl said side' edgeto'deli'ne a first needle receiving opening between saidirst finger` and said side edge, a second elongate stltch finger secured at its base yto`said projection and extending horizontally from said projectionvin parallel relationship' to-said1ir`st stitch finger to define a second needle receiving opening between said li'rst` and'said second fin gers,` the vertical thicknessof Vsaid lirst linger' at anyv lon-y gitudinal pr'ysitionl thereon being greater than vertical thickness of'said second finger at the'v correspndingelon'gitudinal position- 2.` In an loveredge sewingrnachineha-vinga pair of' needlesin side-by-side relationship; athroat platehaving'l a side? edgeftherelonand a projection e'xtendinglaterally fronisaid side edgealirst stitch finger'` secured at-itslbarseir tosaid' projection and extendingrhorizontally from saidAY projectionvhr spacedV parallel relationship to saidA sideii edge, to define a iirstjneedle vreceiving openingv between said irst -ingerY and'V said sidek edge, a' second stitch finger" secred'at its Vbase yto said projection; and v`extending horif' zontally fromsaid projectionv in spaced parallel'r relatiorr'A ship toI said first finger to'ldeline a second needlereceivingt opening between said irst and saidk second finger, saidf stitch lingers having coplanar horizyontalupper side surfaces'and lower side surfaces tapered upwardly from their' respective bases, the lower side surface of said'second Y stitch fnger'being spaced upwardly from. the lower side surface Vof said first. stitch4 linger.

References vcian inv the 'sie Vof this Vpatent UNITED S'I'ATESv PATENTS 1533,96? weis et a1. Jan'. 13,`- .1914* 1,305,051` Berger May`27, 1919 1,717,050 Y Maier l time 11, 1929 

1. IN AN OVEREDGE SEWING MACHINE HAVING A PAIR OF NEEDLES IN SIDE-BY-SIDE RELATIONSHIP; A THROAT PLATE HAVING A SIDE EDGE AND A PROJECTION EXTENDING LATERALLY FROM SAID SIDE EDGE, A FIRST ELONGATE STITCH FINGER SECURED AT ITS BASE TO SAID PROJECTION AND EXTENDING HORIZONTALLY FROM SAID PROJECTION IN SPACED PARALLEL RELATIONSHIP WITH SAID SIDE EDGE TO DEFINE A FIRST NEEDLE RECEIVING OPENING BETWEEN SAID FIRST FINGER AND SAID SIDE EDGE, A SECOND ELONGATE STITCH FINGER SECURED AT ITS BASE TO SAID PROJECTION AND EXTENDING HORIZONTALLY FROM SAID PROJECTION IN PARALLEL RELATIONSHIP TO SAID FIRST STITCH FINGER TO DEFINE A SECOND NEEDLE 